1. Technical Field
The present invention relates generally to a window stop, and more particularly to an improved window securing device for preventing or limiting movement of a window sash.
2. Background of the Invention
Double-hung windows are one of the most common kinds of windows for residential and other structures. Typically, a double-hung window assembly consists of a window frame and a pair of window sashes. The lower sash resides immediately inward of the upper sash so that the sashes overlap and vertically slide parallel to one another along guide rails of the master window jamb of the window assembly. Although window sashes are traditionally made exclusively of wood, such window sashes can be formed of extruded plastic frame members or metal frame members joined at the corners, for example, to form a generally rectangular frame in which the glazing is installed.
Most double-hung windows include a locking mechanism located at the point where the sashes meet when the window assembly is closed. A latch mechanism is fixed on the header of the lower sash and the corresponding latch-receiving mechanism is fixed on the sill of the other sash. When the window sashes are in the closed position, the lock may be secured to prevent any movement of the sashes. The problem associated with these locks is that they are typically difficult to secure either because of the tight tension of the mechanism or the need to align the lock with the latch perfectly before securing. Such locks also fail to provide the user an option to open the window slightly to allow ventilation, while also inhibiting egress in or out through the window.
To limit the relative movement of the sashes, stop or limit devices known as xe2x80x9csash locksxe2x80x9d or xe2x80x9cwindow stopsxe2x80x9d have been developed to solve the above problems. Sash locks in various designs and forms are now available. Typically, the designs include a pawl pivotally mounted in a housing in a stile member of the upper sash. A spring biases the pawl toward an extended position, whereby the pawl is configured to engage the header member of the lower sash to limit movement thereof. An upper rear surface of the pawl is engageable with a back wall of the housing in cooperation with a pivot post or lug to serve to limit rotation of the pawl.
Over-rotation of the pawl has been a problem with this type of sash lock. Occasionally, the lower sash or the user may engage the pawl in such a way that it does not properly engage the back wall of the housing. It has also been found that in applications where large forces are applied to prior art pawls, the back wall of the housing can deform under the increased horizontal force against the back wall imposed by the pawl, and allow the pawl to slide along the back wall and over-rotate, permitting the window to open. Tremendous stress is also exerted on the pivot post or lug that may also result in failure during engagement with the lower sash. In both incidents, over-rotation occurs and the stop fails to adequately limit movement of the lower sash.
Another problem encountered by prior art sash locks is the existence of a gap between the lower end of the pawl and housing when the pawl is extended. This gap allows dust and debris to collect within the cavity over time. Eventually the cavity of the housing becomes impacted with dirt, whereby the proper functioning of the sash lock is impeded. With respect to the manufacture of sash locks, typically, prior art sash lock housings are composed of two or more parts that require assembly. Sash locks incorporating such housings cost more to produce than if unitary housings were utilized.
Accordingly, there is a need for an improved window stop, wherein the stop is simple to manufacture, stronger and more durable, less prone to failure, and cost effective to produce.
The present invention is generally directed to a window securing device for use in a double-hung window assembly having upper and lower sash window frames installed for vertical reciprocal sliding movement relative to each other. The stile member of the upper sash has a recess on the front surface for installing the device into the recess.
The window securing device includes a housing that is configured to be securely retained in the recess provided in the stile of the upper sash so that the faceplate of the housing protrudes slightly ahead of the stile""s surface. The faceplate has an opening that is continuous with an interior cavity of the housing.
A pawl is disposed in the cavity and is configured to move between a retracted position and an extended or securing position. In the securing position, an end of the pawl projects from the opening in the faceplate and is configured to engage an exterior surface of the header of the lower sash to prevent upward vertical movement thereof. The pawl is spring biased to a normally protruding securing position and is movable to a retracted position in the housing. A spring is mounted directly on the pawl via one end that engages the pawl, and the other end of the spring engages the back wall of the housing.
In the securing position, the pawl engages the lower sash frame and prevents further relative sliding movement of the sash frames. The pivotally mounted pawl is manually retractable into the cavity to disengage the lower end of the pawl from the lower sash frame header. The faceplate and the retaining studs are cooperatively engageable to releasably maintain the lower end of the pawl in the retracted position. When the pawl is retracted, relative sliding movement between the sash frames can occur.
In one embodiment of the present invention, the pawl includes a contact edge proximate to its upper end for preventing the pawl from overextending when the lower sash window is intercepted. It transfers and directs the vertical force originating from the sash window into the stile of the upper window sash. This design is more efficient and superior over those that utilize the back wall and the pivot lug to absorb the force.
In another embodiment of the present invention, the pawl also includes a dust tab extending from the lower end of the pawl. The dust tab is a small protrusion that closes the gap between the lower end of the pawl and the lower end of the opening to prevent dust and debris from entering the cavity of the housing.